Rotary Encoder Correction for Transport Roller Misalignment
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Solution Overview
Problem
Conventional rotary encoder methods for transport apparatuses fail to accurately calculate transport speed and timing when the encoder shaft is misaligned with the transport roller, leading to inaccurate length measurements and output signal correlations.
Innovation Solution
A method that involves dividing the output signals from the rotary encoder into n-divided areas, measuring the time taken for each area, calculating correction coefficients based on these times, and applying these corrections to ensure accurate timing calculations even with misalignment, allowing for precise transport speed determination and improved printing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the rotary encoder shaft is misaligned with the transport roller center, then the structure is easier to manufacture and assemble, but the measurement precision of transport speed and timing deteriorates
Solution Approach 1:
The patent performs preliminary measurement of divided area shift times during a calibration phase before actual operation. By measuring the time taken for the encoder to pass through n-divided areas and calculating correction coefficients in advance, the system compensates for misalignment effects during normal operation without requiring precise mechanical alignment.
Solution Approach 2:
The patent changes the parameter approach by introducing correction coefficients that adjust the measured divided area shift times. Instead of relying on raw encoder signals that are affected by misalignment, the system applies calculated correction factors to obtain accurate transport speed values, thereby decoupling measurement precision from mechanical alignment precision.
2Measurement precision
If the rotary encoder shaft is precisely aligned with the transport roller center, then the measurement precision of transport speed is improved, but the device complexity and assembly difficulty increase
Solution Approach 1:
The system performs self-calibration by automatically measuring divided area shift times and calculating correction coefficients during a calibration phase. This self-service mechanism eliminates the need for manual precise alignment during assembly, as the system autonomously adapts to the actual misalignment state and compensates for it through calculated corrections during operation.
Solution Approach 2:
The patent implements feedback by continuously using the measured divided area shift times to calculate correction coefficients, which are then applied to correct future timing measurements. This feedback loop ensures that timing calculations remain accurate despite persistent misalignment, as the system continuously adapts to the actual physical state.
3Measurement precision
If correction coefficients are calculated for each divided area, then the measurement precision is improved, but the device complexity and processing time increase
Solution Approach 1:
The patent segments the encoder output into n-divided areas, where each area corresponds to a specific angular range. By measuring and calculating correction coefficients for each segmented area separately, the system can accurately compensate for misalignment effects in each region, thereby improving overall measurement precision while maintaining manageable computational complexity through structured division of the measurement task.
Data Source
AI summary
A rotary encoder correcting method for a transport apparatus having a rotary encoder for outputting output signals in response to rotation of a transport roller. The method includes the steps of setting beforehand the number of n-divided output signals obtained by dividing, by n, the number of output signals outputted from the rotary encoder with one rotation of the transport roller; measuring a divided area shift time for each divided area when a printing medium is transported at constant speed and each time the number of output signals agrees with the number of n-divided output signals; and calculating a correction coefficient for each divided area based on the divided area shift time. The divided area shift time is corrected for each divided area of the rotary encoder based on each correction coefficient when a process is carried out on the printing medium.